分，则知天地之气（亦与始刺浅之，而来血气意合）。针入二分，则知呼吸出入，上下水火之
By measuring the *cun* (Chinese inch), one can comprehend the Qi of Heaven and Earth (this also aligns with the intent of initial superficial needling regarding the movement of Qi and Blood). When the needle is inserted two *fen* (one-tenth of a cun) deep, one can perceive the inhalation and exhalation, as well as the relationships between the upper and lower parts, and Water and Fire.